According to the preamble to the united states constitution, our nation needed to form a "more perfect union." which document had been the "law of the land" since 1781 and now needed to be replaced in 1787? a) the virginia plan b) the bill of rights c) the new jersey plan d) the articles of confederation

The Articles of Confederation.

Explanation:

After the USA won its independence, the highest law was NOT constitution but the Articles of Confederation that formed weak central government. Under that document, the central government could not collect taxes, coin, money, make treaties with other countries, regulate commerce, etc. In 1787, it became obvious that country cannot function that way. Therefore, the delegates met in Philadelphia to find a new solution. This meeting became known as the Constitutional Convention that eventually gave birth to the Constitution of the United States that created strong central government with the executive branch, legislative branch, and judicial branch. Including checks and balances.

the answer to your question is,

old stone age.

-mabel < 3